Applying results from clinical trials: tranexamic acid in trauma patients

The Effect of Topical Tranexamic Acid on Postrhinoplasty Periorbital Ecchymosis and Eyelid Edema

BACKGROUND

This study aimed to examine the effectiveness of topical tranexamic acid application in overcoming periorbital ecchymosis and eyelid edema in patients who have undergone open-technique rhinoplasty.

METHODS

Fifty patients were included in the study and divided into two groups: those who had topical tranexamic acid applied and those who did not (controls). In the tranexamic acid group, tranexamic acid-soaked pledgets were placed under the skin flap in a way that both sides could reach the osteotomy area and left for 5 minutes. In the control group, isotonic saline-soaked pledgets were placed under the skin flap in the same manner and left for 5 minutes. Digital photographs were obtained on postoperative days 1, 3, and 7. Eyelid edema and periorbital ecchymosis were scored by two different examiners and averaged for comparison.

RESULTS

Edema that developed in the patients who had tranexamic acid applied was significantly less than in the control group on postoperative day 1. There was no difference between the two groups on postoperative day 3 or 7. Ecchymosis that developed in patients who had tranexamic acid applied was significantly less than in the control group on all days.

CONCLUSIONS

Topical tranexamic acid applied to the surgical field immediately after osteotomy in rhinoplasty surgery reduces the development of postoperative periorbital ecchymosis. In addition, the topical tranexamic acid application also reduces the development of eyelid edema in the early postoperative period.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

The Effectiveness of Prehospital Administration of Tranexamic Acid in Reducing Mortality in Trauma Patients: An Overview

Tranexamic acid (TXA) is an antifibrinolytic drug that reduces bleeding by inhibiting plasminogen activation and fibrin clot degradation. Its role in prehospital trauma management remains unclear. This article aims to systematically review the current evidence on the effect of prehospital TXA administration on mortality in adult and pediatric trauma patients. A literature search was conducted of PubMed, Web of Science, Scopus, and Cochrane databases from March 2023 to August 2023 for studies evaluating the impact of prehospital TXA use on trauma mortality. Inclusion criteria were articles published in the English language in the past 20 years focusing on clinical outcomes of prehospital TXA administration. Data on all-cause mortality, thromboembolic events, and time to TXA administration were extracted. In adult trauma, prehospital TXA appears to reduce early all-cause mortality when given within three hours of injury without increasing thromboembolic risks. Some studies found decreased delayed mortality, while others found no difference. In pediatric trauma, preliminary evidence suggests TXA may lower in-hospital mortality in hemodynamically unstable patients, though higher doses may increase seizure risk. Early prehospital administration of TXA within three hours of adult trauma may reduce mortality through improved hemorrhage control. Potential benefits in pediatric trauma warrant further investigation, balancing efficacy against safety risks such as seizures from high doses. Well-designed randomized trials are needed to validate optimal TXA dosing strategies across age groups and injury severity levels.

State-by-state estimates of avoidable trauma mortality with early and liberal versus delayed or restricted administration of tranexamic acid

OBJECTIVE

Early administration of tranexamic acid (TXA) has been shown to save lives in trauma patients, and some U.S. emergency medical systems (EMS) have begun providing this therapy prehospital. Treatment protocols vary from state to state: Some offer TXA broadly to major trauma patients, others reserve it for patients meeting vital sign criteria, and still others defer TXA entirely pending a hospital evaluation. The purpose of this study is to compare the avoidable mortality achievable under each of these strategies, and to report on the various approaches used by EMS.

METHODS

We used the National Center for Health Statistics Underlying Cause of Death data to identify a TXA-naïve population of trauma patients who died from 2007 to 2012 due to hemorrhage. We estimated the proportion of deaths where the patient was hypotensive or tachycardic using the National Trauma Data Bank. We used avoidable mortality risk ratios from the landmark CRASH 2 study to calculate lives saved had TXA been given within one hour of injury based on a clinician's gestalt the patient was at risk for significant hemorrhage; had it been reserved only for hypotensive or tachycardic patients; or had it been given between hours one to three of injury, considered here as a surrogate for deferring the question to the receiving hospital.

RESULTS

Had TXA been given within 1 hour of injury, an average of 3409 deaths per year could have been averted nationally. Had TXA been given between one and three hours after injury, 2236 deaths per year could have been averted. Had TXA only been given to either tachycardic or hypotensive trauma patients, 1371 deaths per year could have been averted. Had TXA only been given to hypotensive trauma patients, 616 deaths per year could have been averted. Similar trends are seen at the individual state level. A review of EMS practices found 15 statewide protocols that allow EMS providers to administer TXA for trauma.

CONCLUSION

Providing early TXA to persons at risk of significant hemorrhage has the potential to prevent many deaths from trauma, yet most states do not offer it in statewide prehospital treatment protocols.

Including random centre effects in design, analysis and presentation of multi-centre trials

Background

In large multicentre trials in diverse settings, there is uncertainty about the need to adjust for centre variation in design and analysis. A key distinction is the difference between variation in outcome (independent of treatment) and variation in treatment effect. Through re-analysis of the CRASH-2 trial (2010), this study clarifies when and how to use multi-level models for multicentre studies with binary outcomes.

Methods

CRASH-2 randomised 20,127 trauma patients across 271 centres and 40 countries to either single-dose tranexamic acid or identical placebo, with all-cause death at 4 weeks the primary outcome. The trial data had a hierarchical structure, with patients nested in hospitals which in turn are nested within countries. Reanalysis of CRASH-2 trial data assessed treatment effect and both patient and centre level baseline covariates as fixed effects in logistic regression models. Random effects were included to assess where there was variation between countries, and between centres within countries, both in underlying risk of death and in treatment effect.

Results

In CRASH-2, there was significant variation between countries and between centres in death at 4 weeks, but absolutely no differences between countries or centres in the effect of treatment. Average treatment effect was not altered after accounting for centre and country variation in this study.

Conclusions

It is important to distinguish between underlying variation in outcomes and variation in treatment effects; the former is common but the latter is not. Stratifying randomisation by centre overcomes many statistical problems and including random intercepts in analysis may increase power and decrease bias in mean and standard error estimates.

Trial registration

Current Controlled Trials ISRCTN86750102, ClinicalTrials.gov NCT00375258, and South African Clinical Trial Register DOH-27-0607-1919

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05266-w.

Effect of tranexamic acid on intracranial haemorrhage and infarction in patients with traumatic brain injury: a pre-planned substudy in a sample of CRASH-3 trial patients

BACKGROUND

Early tranexamic acid (TXA) treatment reduces head injury deaths after traumatic brain injury (TBI). We used brain scans that were acquired as part of the routine clinical practice during the CRASH-3 trial (before unblinding) to examine the mechanism of action of TXA in TBI. Specifically, we explored the potential effects of TXA on intracranial haemorrhage and infarction.

METHODS

This is a prospective substudy nested within the CRASH-3 trial, a randomised placebo-controlled trial of TXA (loading dose 1 g over 10 min, then 1 g infusion over 8 hours) in patients with isolated head injury. CRASH-3 trial patients were recruited between July 2012 and January 2019. Participants in the current substudy were a subset of trial patients enrolled at 10 hospitals in the UK and 4 in Malaysia, who had at least one CT head scan performed as part of the routine clinical practice within 28 days of randomisation. The primary outcome was the volume of intraparenchymal haemorrhage (ie, contusion) measured on a CT scan done after randomisation. Secondary outcomes were progressive intracranial haemorrhage (post-randomisation CT shows >25% of volume seen on pre-randomisation CT), new intracranial haemorrhage (any haemorrhage seen on post-randomisation CT but not on pre-randomisation CT), cerebral infarction (any infarction seen on any type of brain scan done post-randomisation, excluding infarction seen pre-randomisation) and intracranial haemorrhage volume (intraparenchymal + intraventricular + subdural + epidural) in those who underwent neurosurgical haemorrhage evacuation. We planned to conduct sensitivity analyses excluding patients who were severely injured at baseline. Dichotomous outcomes were analysed using relative risks (RR) or hazard ratios (HR), and continuous outcomes using a linear mixed model.

RESULTS

1767 patients were included in this substudy. One-third of the patients had a baseline GCS (Glasgow Coma Score) of 3 (n=579) and 24% had unilateral or bilateral unreactive pupils. 46% of patients were scanned pre-randomisation and post-randomisation (n=812/1767), 19% were scanned only pre-randomisation (n=341/1767) and 35% were scanned only post-randomisation (n=614/1767). In all patients, there was no evidence that TXA prevents intraparenchymal haemorrhage expansion (estimate=1.09, 95% CI 0.81 to 1.45) or intracranial haemorrhage expansion in patients who underwent neurosurgical haemorrhage evacuation (n=363) (estimate=0.79, 95% CI 0.57 to 1.11). In patients scanned pre-randomisation and post-randomisation (n=812), there was no evidence that TXA reduces progressive haemorrhage (adjusted RR=0.91, 95% CI 0.74 to 1.13) and new haemorrhage (adjusted RR=0.85, 95% CI 0.72 to 1.01). When patients with unreactive pupils at baseline were excluded, there was evidence that TXA prevents new haemorrhage (adjusted RR=0.80, 95% CI 0.66 to 0.98). In patients scanned post-randomisation (n=1431), there was no evidence of an increase in infarction with TXA (adjusted HR=1.28, 95% CI 0.93 to 1.76). A larger proportion of patients without (vs with) a post-randomisation scan died from head injury (38% vs 19%: RR=1.97, 95% CI 1.66 to 2.34, p<0.0001).

CONCLUSION

TXA may prevent new haemorrhage in patients with reactive pupils at baseline. This is consistent with the results of the CRASH-3 trial which found that TXA reduced head injury death in patients with at least one reactive pupil at baseline. However, the large number of patients without post-randomisation scans and the possibility that the availability of scan data depends on whether a patient received TXA, challenges the validity of inferences made using routinely collected scan data. This study highlights the limitations of using routinely collected scan data to examine the effects of TBI treatments.

TRIAL REGISTRATION NUMBER

ISRCTN15088122.

A nested randomised trial of the effect of tranexamic acid on intracranial haemorrhage and infarction in traumatic brain injury (CRASH-3 trial intracranial bleeding mechanistic study): Statistical analysis plan

Background: The CRASH-3 trial is a randomised trial on the effect of tranexamic acid (TXA) versus placebo on death and disability in traumatic brain injury (TBI). The CRASH-3 intracranial bleeding mechanistic study (IBMS) is a randomised trial nested within the CRASH-3 trial to examine the effect of TXA versus placebo on intracranial bleeding and infarction. Methods: Patients eligible for the CRASH-3 trial, with a GCS of 12 or less or intracranial bleeding on a pre-randomisation CT scan are eligible for the IBMS. The occurrence of intracranial bleeding, infarction, haemorrhagic oedematous lesions, mass effect and haemorrhage evacuation is examined within 28 days of randomisation using routinely collected brain scans. The primary outcome is the volume of intra-parenchymal bleeding in patients randomised within three hours of injury (adjusted for prognostic covariates). Secondary outcomes include a composite "poor" outcome, progressive and new intracranial bleeding, intracranial bleeding after neurosurgery and cerebral infarcts seen up to 28 days post-randomisation. All outcomes will be compared between treatment groups. Statistical analyses: The primary outcome will be analysed using a covariate adjusted linear mixed model. The same analysis will be done separately for patients who undergo haemorrhage evacuation post-randomisation. We will express the effect of TXA on the composite outcome, new and progressive bleeding using relative risks and 95% CIs, and on cerebral infarcts using hazard ratios and 95% CIs. We will conduct sensitivity analyses assuming missing data are MCAR or MNAR. Conclusion: The IBMS will provide information on the mechanism of action of TXA in TBI. This pre-specified statistical analysis plan is a technical extension of the published protocol. Trial registration: The CRASH-3 trial was prospectively registered at the International Standard Randomised Controlled Trials registry (19 July 2011) and ClinicalTrials.gov (25 July 2011). The registries were updated with details for the IBMS on 20 December 2016.

Structural studies of plasmin inhibition

Plasminogen (Plg) is the zymogen form of the serine protease plasmin (Plm), and it plays a crucial role in fibrinolysis as well as wound healing, immunity, tissue remodeling and inflammation. Binding to the targets via the lysine-binding sites allows for Plg activation by plasminogen activators (PAs) present on the same target. Cellular uptake of fibrin degradation products leads to apoptosis, which represents one of the pathways for cross-talk between fibrinolysis and tissue remodeling. Therapeutic manipulation of Plm activity plays a vital role in the treatments of a range of diseases, whereas Plm inhibitors are used in trauma and surgeries as antifibrinolytic agents. Plm inhibitors are also used in conditions such as angioedema, menorrhagia and melasma. Here, we review the rationale for the further development of new Plm inhibitors, with a particular focus on the structural studies of the active site inhibitors of Plm. We compare the binding mode of different classes of inhibitors and comment on how it relates to their efficacy, as well as possible future developments.

A nested randomised trial of the effect of tranexamic acid on intracranial haemorrhage and infarction in traumatic brain injury (CRASH-3 trial intracranial bleeding mechanistic study): Statistical analysis plan

Background: The CRASH-3 trial is a randomised trial on the effect of tranexamic acid (TXA) on death and disability in traumatic brain injury (TBI). The CRASH-3 intracranial bleeding mechanistic study (IBMS) is a randomised trial nested within the CRASH-3 trial to examine the effect of TXA on intracranial bleeding and infarction. Methods: Patients eligible for the CRASH-3 trial, with a GCS of 12 or less or intracranial bleeding on a pre-randomisation CT scan are eligible for the IBMS. The occurrence of intracranial bleeding, infarction, haemorrhagic oedematous lesions, mass effect and haemorrhage evacuation is examined within 28 days of randomisation using routinely collected brain scans. The primary outcome is the volume of intra-parenchymal bleeding in patients randomised within three hours of injury (adjusted for prognostic covariates). Secondary outcomes include a composite "poor" outcome, progressive and new intracranial bleeding, intracranial bleeding after neurosurgery and cerebral infarcts seen up to 28 days post-randomisation. All outcomes will be compared between treatment groups. Statistical analyses: The primary outcome will be analysed using a covariate adjusted linear mixed model. The same analysis will be done separately for patients who undergo haemorrhage evacuation post-randomisation. We will express the effect of TXA on the composite outcome, new and progressive bleeding using relative risks and 95% CIs, and on cerebral infarcts using hazard ratios and 95% CIs. We will conduct sensitivity analyses assuming missing data are MCAR or MNAR. Conclusion: The IBMS will provide information on the mechanism of action of TXA in TBI. This pre-specified statistical analysis plan is a technical extension of the published protocol. Trial registration: The CRASH-3 trial was prospectively registered at the International Standard Randomised Controlled Trials registry (19 July 2011) and ClinicalTrials.gov (25 July 2011). The registries were updated with details for the IBMS on 20 December 2016.

A nested randomised trial of the effect of tranexamic acid on intracranial haemorrhage and infarction in traumatic brain injury (CRASH-3 trial intracranial bleeding mechanistic study): Statistical analysis plan

Background: The CRASH-3 trial is a randomised trial on the effect of tranexamic acid (TXA) on death and disability in traumatic brain injury (TBI). The CRASH-3 intracranial bleeding mechanistic study (IBMS) is a randomised trial nested within the CRASH-3 trial to examine the effect of TXA on intracranial bleeding and infarction. Methods: Patients eligible for the CRASH-3 trial, with a GCS of 12 or less or intracranial bleeding on a pre-randomisation CT scan are eligible for the IBMS. The occurrence of intracranial bleeding, infarction, haemorrhagic oedematous lesions, mass effect and haemorrhage evacuation is examined within 28 days of randomisation using routinely collected brain scans. The primary outcome is the volume of intracranial bleeding in patients randomised within three hours of injury (adjusted for prognostic covariates). Secondary outcomes include progressive and new intracranial bleeding, intracranial bleeding after neurosurgery and new cerebral infarcts up to 28 days post-randomisation. All outcomes will be compared between treatment groups. Statistical analyses: The primary outcome will be analysed using absolute measures (ANCOVA) and relative measures (ratios). The same analysis will be done separately for patients who undergo haemorrhage evacuation post-randomisation. We will express the effect of TXA on new and progressive bleeding using relative risks and 95% CIs, and on cerebral infarcts using hazard ratios and 95% CIs. If any missing post-randomisation scans appear to be missing not at random, we will conduct sensitivity analyses to explore the implications. Conclusion: The IBMS will provide information on the mechanism of action of TXA in TBI. This pre-specified statistical analysis plan is a technical extension of the published protocol. Trial registration: The CRASH-3 trial was prospectively registered at the International Standard Randomised Controlled Trials registry (19 July 2011) and ClinicalTrials.gov (25 July 2011). The registries were updated with details for the IBMS on 20 December 2016.

Effect of treatment delay on the effectiveness and safety of antifibrinolytics in acute severe haemorrhage: a meta-analysis of individual patient-level data from 40 138 bleeding patients

BACKGROUND

Antifibrinolytics reduce death from bleeding in trauma and post-partum haemorrhage. We examined the effect of treatment delay on the effectiveness of antifibrinolytics.

METHODS

We did an individual patient-level data meta-analysis of randomised trials done with more than 1000 patients that assessed antifibrinolytics in acute severe bleeding. We identified trials done between Jan 1, 1946, and April 7, 2017, from MEDLINE, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, PubMed, Popline, and the WHO International Clinical Trials Registry Platform. The primary measure of treatment benefit was absence of death from bleeding. We examined the effect of treatment delay on treatment effectiveness using logistic regression models. We investigated the effect of measurement error (misclassification) in sensitivity analyses. This study is registered with PROSPERO, number 42016052155.

FINDINGS

We obtained data for 40 138 patients from two randomised trials of tranexamic acid in acute severe bleeding (traumatic and post-partum haemorrhage). Overall, there were 3558 deaths, of which 1408 (40%) were from bleeding. Most (884 [63%] of 1408) bleeding deaths occurred within 12 h of onset. Deaths from post-partum haemorrhage peaked 2-3 h after childbirth. Tranexamic acid significantly increased overall survival from bleeding (odds ratio [OR] 1·20, 95% CI 1·08-1·33; p=0·001), with no heterogeneity by site of bleeding (interaction p=0·7243). Treatment delay reduced the treatment benefit (p<0·0001). Immediate treatment improved survival by more than 70% (OR 1·72, 95% CI 1·42-2·10; p<0·0001). Thereafter, the survival benefit decreased by 10% for every 15 min of treatment delay until 3 h, after which there was no benefit. There was no increase in vascular occlusive events with tranexamic acid, with no heterogeneity by site of bleeding (p=0·5956). Treatment delay did not modify the effect of tranexamic acid on vascular occlusive events.

INTERPRETATION

Death from bleeding occurs soon after onset and even a short delay in treatment reduces the benefit of tranexamic acid administration. Patients must be treated immediately. Further research is needed to deepen our understanding of the mechanism of action of tranexamic acid.

FUNDING

UK NIHR Health Technology Assessment programme, Pfizer, BUPA Foundation, and J P Moulton Charitable Foundation (CRASH-2 trial). London School of Hygiene & Tropical Medicine, Pfizer, UK Department of Health, Wellcome Trust, and Bill & Melinda Gates Foundation (WOMAN trial).

Biomaterials and Advanced Technologies for Hemostatic Management of Bleeding

Bleeding complications arising from trauma, surgery, and as congenital, disease-associated, or drug-induced blood disorders can cause significant morbidities and mortalities in civilian and military populations. Therefore, stoppage of bleeding (hemostasis) is of paramount clinical significance in prophylactic, surgical, and emergency scenarios. For externally accessible injuries, a variety of natural and synthetic biomaterials have undergone robust research, leading to hemostatic technologies including glues, bandages, tamponades, tourniquets, dressings, and procoagulant powders. In contrast, treatment of internal noncompressible hemorrhage still heavily depends on transfusion of whole blood or blood's hemostatic components (platelets, fibrinogen, and coagulation factors). Transfusion of platelets poses significant challenges of limited availability, high cost, contamination risks, short shelf-life, low portability, performance variability, and immunological side effects, while use of fibrinogen or coagulation factors provides only partial mechanisms for hemostasis. With such considerations, significant interdisciplinary research endeavors have been focused on developing materials and technologies that can be manufactured conveniently, sterilized to minimize contamination and enhance shelf-life, and administered intravenously to mimic, leverage, and amplify physiological hemostatic mechanisms. Here, a comprehensive review regarding the various topical, intracavitary, and intravenous hemostatic technologies in terms of materials, mechanisms, and state-of-art is provided, and challenges and opportunities to help advancement of the field are discussed.

A nested mechanistic sub-study into the effect of tranexamic acid versus placebo on intracranial haemorrhage and cerebral ischaemia in isolated traumatic brain injury: study protocol for a randomised controlled trial (CRASH-3 Trial Intracranial Bleeding Mechanistic Sub-Study [CRASH-3 IBMS])

Background

Tranexamic acid prevents blood clots from breaking down and reduces bleeding. However, it is uncertain whether tranexamic acid is effective in traumatic brain injury. The CRASH-3 trial is a randomised controlled trial that will examine the effect of tranexamic acid (versus placebo) on death and disability in 13,000 patients with traumatic brain injury. The CRASH-3 trial hypothesizes that tranexamic acid will reduce intracranial haemorrhage, which will reduce the risk of death. Although it is possible that tranexamic acid will reduce intracranial bleeding, there is also a potential for harm. In particular, tranexamic acid may increase the risk of cerebral thrombosis and ischaemia. The protocol detailed here is for a mechanistic sub-study nested within the CRASH-3 trial. This mechanistic sub-study aims to examine the effect of tranexamic acid (versus placebo) on intracranial bleeding and cerebral ischaemia.

Methods

The CRASH-3 Intracranial Bleeding Mechanistic Sub-Study (CRASH-3 IBMS) is nested within a prospective, double-blind, multi-centre, parallel-arm randomised trial called the CRASH-3 trial. The CRASH-3 IBMS will be conducted in a cohort of approximately 1000 isolated traumatic brain injury patients enrolled in the CRASH-3 trial. In the CRASH-3 IBMS, brain scans acquired before and after randomisation are examined, using validated methods, for evidence of intracranial bleeding and cerebral ischaemia. The primary outcome is the total volume of intracranial bleeding measured on computed tomography after randomisation, adjusting for baseline bleeding volume. Secondary outcomes include progression of intracranial haemorrhage (from pre- to post-randomisation scans), new intracranial haemorrhage (seen on post- but not pre-randomisation scans), intracranial haemorrhage following neurosurgery, and new focal ischaemic lesions (seen on post-but not pre-randomisation scans). A linear regression model will examine whether receipt of the trial treatment can predict haemorrhage volume. Bleeding volumes and new ischaemic lesions will be compared across treatment groups using relative risks and 95% confidence intervals.

Discussion

The CRASH-3 IBMS will provide an insight into the mechanism of action of tranexamic acid in traumatic brain injury, as well as information about the risks and benefits. Evidence from this trial could inform the management of patients with traumatic brain injury.

Trial registration

The CRASH-3 trial was prospectively registered and the CRASH-3 IBMS is an addition to the original protocol registered at the International Standard Randomised Controlled Trials registry (ISRCTN15088122) 19 July 2011, and ClinicalTrials.gov on 25 July 2011 (NCT01402882).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2073-6) contains supplementary material, which is available to authorized users.

Tranexamic acid in bleeding trauma patients: an exploration of benefits and harms

Background

The CRASH-2 trial showed that tranexamic acid (TXA) administration reduces mortality in bleeding trauma patients. However, the effect appeared to depend on how soon after injury TXA treatment was started. Treatment within 3 h reduced bleeding deaths whereas treatment after 3 h increased the risk. We examine how patient characteristics vary by time to treatment and explore whether any such variations explain the time-dependent treatment effect.

Methods

Exploratory analysis were carried out, including per-protocol analyses, of data from the CRASH-2 trial, a randomised placebo-controlled trial of the effect of TXA on mortality in 20,211 trauma patients with, or at risk of, significant bleeding. We examine how patient characteristics (age, type of injury, presence or absence of head injury, Glasgow coma scale (GCS), systolic blood pressure and capillary refill time) vary with time to treatment and use univariable (restriction) and multivariable methods to examine whether any such variations explain the time-dependent effect of TXA. If not explained by differences in patient characteristics, we planned to conduct separate prespecified subgroup analyses for the early benefit and late harm.

Results

There was no substantial variation in age or capillary refill by time to treatment. However, the proportion of patients with blunt trauma, the proportion with head injury and mean systolic blood pressure increased as time to treatment increased. Mean GCS decreased as time to treatment increased. Analyses restricted to patients with blunt trauma, those without head injury and those with a systolic blood pressure <100 mmHg showed that these characteristics did not explain the time-dependent treatment effect. In a multivariable analysis the interaction with time to treatment remained highly significant (p < 0.0001). Separate subgroup analyses that examine how the benefits of early TXA treatment and the harms of late TXA treatment vary by systolic blood pressure (≤75, 76–89, >89 mmHg); GCS (severe 3–8, moderate 9–12, mild 13–15); and type of injury (penetrating versus blunt) showed no significant heterogeneity.

Conclusions

The time-dependent effect of TXA in bleeding trauma patients is not explained by the type of injury, the presence or absence of head injury or systolic blood pressure. When given within 3 h of injury, TXA reduces death due to bleeding regardless of type of injury, GCS or blood pressure.

Trial registration

ClinicalTrials.gov, NCT00375258. Registered on 11 September 2006.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1750-1) contains supplementary material, which is available to authorized users.

Tranexamic acid and trauma-induced coagulopathy

Tranexamic acid (TXA) is a synthetic derivative of the amino acid lysine that inhibits fibrinolysis by blocking the interaction of plasminogen with the lysine residues of fibrin. Historically, TXA is commonly used for reduction of blood loss in perioperative situations, while recently it has attracted attention for clinical use in the trauma field. In 2010, the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage 2 (CRASH-2) trial demonstrated that intravenous administration of TXA improved mortality significantly in trauma patients with significant bleeding. After the launch of its sensational results, the main stream treatment protocol in trauma changed worldwide to include TXA administration.

In this review, first we summarize the recent evidence or recommendations in the related guidelines concerning TXA. Also, we next tried to explore in detail not only the benefits but also the harm introduced by TXA in trauma patients, because the main adverse event results for TXA, such as vascular occlusive events in the CRASH-2 trial, are still being discussed in several papers. Thus, we briefly summarized the evidence for the safety of TXA administration by a systematic review method using observational studies. Consequently, the pooled relative risk for venous thromboembolisms was 1.61 (95% CI, 0.86–3.01), indicating a non-significant increase in the venous thromboembolism risk of TXA therapy.

Regarding the basic mechanism, TXA potentially possesses the risk of venous thromboembolisms, so it should be used cautiously and selectively. Further investigation is needed to delineate the optimal targeted trauma patients to earn the maximum survival benefits with minimized risk of thrombotic complications.

Effects of tranexamic acid on platelet function and thrombin generation (ETAPlaT): WOMAN trial sub-study

Background. Postpartum haemorrhage (PPH) is a leading cause of maternal death. Tranexamic acid (TXA) has the potential to reduce bleeding and a large randomized placebo controlled trial of its effect in women with PPH (The WOMAN trial) is underway. TXA might also affect coagulation factors and platelets.  Objectives. To examine the effect of TXA on thrombin generation, platelet function, fibrinogen, D-dimer and coagulation factors in women with PPH.  Methods. We will conduct a sub-study within the WOMAN trial. Women with clinically diagnosed primary PPH after vaginal or caesarean delivery are eligible for inclusion. Blood samples will be collected at baseline and 30 minutes after the first dose of study treatment. Using platelet poor plasma we will measure thrombin generation, fibrinogen, D-dimer, factor V and VIII, and Von Willebrand factor. Platelet function will be evaluated in whole blood using Multiplate® tests. Outcomes. The primary outcome is the effect of TXA on thrombin generation. Secondary outcomes include the effect of TXA on platelet function, fibrinogen, D-dimer and coagulation factors.

Interpretation of the evidence for the efficacy and safety of statin therapy

This Review is intended to help clinicians, patients, and the public make informed decisions about statin therapy for the prevention of heart attacks and strokes. It explains how the evidence that is available from randomised controlled trials yields reliable information about both the efficacy and safety of statin therapy. In addition, it discusses how claims that statins commonly cause adverse effects reflect a failure to recognise the limitations of other sources of evidence about the effects of treatment. Large-scale evidence from randomised trials shows that statin therapy reduces the risk of major vascular events (ie, coronary deaths or myocardial infarctions, strokes, and coronary revascularisation procedures) by about one-quarter for each mmol/L reduction in LDL cholesterol during each year (after the first) that it continues to be taken. The absolute benefits of statin therapy depend on an individual's absolute risk of occlusive vascular events and the absolute reduction in LDL cholesterol that is achieved. For example, lowering LDL cholesterol by 2 mmol/L (77 mg/dL) with an effective low-cost statin regimen (eg, atorvastatin 40 mg daily, costing about £2 per month) for 5 years in 10 000 patients would typically prevent major vascular events from occurring in about 1000 patients (ie, 10% absolute benefit) with pre-existing occlusive vascular disease (secondary prevention) and in 500 patients (ie, 5% absolute benefit) who are at increased risk but have not yet had a vascular event (primary prevention). Statin therapy has been shown to reduce vascular disease risk during each year it continues to be taken, so larger absolute benefits would accrue with more prolonged therapy, and these benefits persist long term. The only serious adverse events that have been shown to be caused by long-term statin therapy-ie, adverse effects of the statin-are myopathy (defined as muscle pain or weakness combined with large increases in blood concentrations of creatine kinase), new-onset diabetes mellitus, and, probably, haemorrhagic stroke. Typically, treatment of 10 000 patients for 5 years with an effective regimen (eg, atorvastatin 40 mg daily) would cause about 5 cases of myopathy (one of which might progress, if the statin therapy is not stopped, to the more severe condition of rhabdomyolysis), 50-100 new cases of diabetes, and 5-10 haemorrhagic strokes. However, any adverse impact of these side-effects on major vascular events has already been taken into account in the estimates of the absolute benefits. Statin therapy may cause symptomatic adverse events (eg, muscle pain or weakness) in up to about 50-100 patients (ie, 0·5-1·0% absolute harm) per 10 000 treated for 5 years. However, placebo-controlled randomised trials have shown definitively that almost all of the symptomatic adverse events that are attributed to statin therapy in routine practice are not actually caused by it (ie, they represent misattribution). The large-scale evidence available from randomised trials also indicates that it is unlikely that large absolute excesses in other serious adverse events still await discovery. Consequently, any further findings that emerge about the effects of statin therapy would not be expected to alter materially the balance of benefits and harms. It is, therefore, of concern that exaggerated claims about side-effect rates with statin therapy may be responsible for its under-use among individuals at increased risk of cardiovascular events. For, whereas the rare cases of myopathy and any muscle-related symptoms that are attributed to statin therapy generally resolve rapidly when treatment is stopped, the heart attacks or strokes that may occur if statin therapy is stopped unnecessarily can be devastating.

USE OF TRANEXAMIC ACID IN TRAUMA PATIENTS: AN ANALYSIS OF COST-EFFECTIVENESS FOR USE IN BRAZIL

INTRODUCTION

Use of tranexamic acid (TXA) in trauma has been the subject of growing interest by researchers and health professionals. However, there are still several open questions regarding its use. In some aspects medical literature is controversial. The points of disagreement among experts include questions such as: Which patients should receive TXA in trauma? Should treatment be performed in the pre-hospital environment? Is there any need for laboratory parameters before starting TXA treatment? What is the drug safety profile? The main issue on which there is still no basis in literature is: What is the indication for treatment within massive transfusion protocols?

OBJECTIVE

Answer the questions proposed based on critical evaluation of the evidence gathered so far and carry out a study of cost-effectiveness of TXA use in trauma adapted to the Brazilian reality.

METHODS

A literature review was performed through searching Pubmed.com, Embase and Cab Abstract by headings "tranexamic AND trauma", in all languages, yielding 426 articles. Manuscripts reporting on TXA utilization for elective procedures were excluded, remaining 79 articles. Fifty-five articles were selected, and critically evaluated in order to answer study questions. The evaluation of cost effectiveness was performed using CRASH-2 trial data and Brazilian official population data.

RESULTS

TXA is effective and efficient, and should be administered to a wide range of patients, including those with indication evaluated in research protocols and current indication criteria for TXA should be expanded. As for the cost-effectiveness, the TXA proved to be cost-effective with an average cost of R$ 61.35 (currently US$16) per year of life saved.

CONCLUSION

The use of TXA in trauma setting seems to be effective, efficient and cost-effective in the various groups of polytrauma patients. Its use in massive transfusion protocols should be the subject of further investigations.

Disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by widespread intravascular activation of coagulation that can be caused by infectious insults (such as sepsis) and non-infectious insults (such as trauma). The main pathophysiological mechanisms of DIC are inflammatory cytokine-initiated activation of tissue factor-dependent coagulation, insufficient control of anticoagulant pathways and plasminogen activator inhibitor 1-mediated suppression of fibrinolysis. Together, these changes give rise to endothelial dysfunction and microvascular thrombosis, which can cause organ dysfunction and seriously affect patient prognosis. Recent observations have pointed to an important role for extracellular DNA and DNA-binding proteins, such as histones, in the pathogenesis of DIC. The International Society on Thrombosis and Haemostasis (ISTH) established a DIC diagnostic scoring system consisting of global haemostatic test parameters. This scoring system has now been well validated in diverse clinical settings. The theoretical cornerstone of DIC management is the specific and vigorous treatment of the underlying conditions, and DIC should be simultaneously managed to improve patient outcomes. The ISTH guidance for the treatment of DIC recommends treatment strategies that are based on current evidence. In this Primer, we provide an updated overview of the pathophysiology, diagnosis and management of DIC and discuss the future directions of basic and clinical research in this field.

Left ventricle thrombus after tranexamic acid for spine surgery in an HIV-positive patient

BACKGROUND CONTEXT

Our case highlights the underappreciated thrombotic risks of tranexamic acid (TXA) use in non-cardiac surgery and emphasizes the need to elucidate these risks with appropriate clinical trials.

PURPOSE

The use of TXA in non-cardiac surgery has significantly expanded in the past 5 years, especially after the 2010 publication of the CRASH-2 Trial. We submit a case with the intent to highlight the thrombotic risk of TXA use during non-cardiac surgery and discuss the need for careful risk stratification before the use of TXA in this context.

STUDY DESIGN

A 66-year-old man with long-standing HIV infection, hypertension, and no history of coronary artery disease (CAD) presented for revision spinal fusion surgery with the use of TXA is presented.

METHODS

To limit perioperative blood loss, the case patient received TXA intraoperatively. His operative course was uneventful.

RESULTS

During the first 12 hours postoperatively the patient was noted to have persistent tachycardia and ST-elevation on electrocardiogram. Echocardiography showed a new apical wall motion abnormality and a left ventricle thrombus; cardiac catheterization confirmed two-vessel CAD, treated with a bare-metal stent and anticoagulation.

CONCLUSIONS

The thrombotic risks of TXA use in non-cardiac surgery have yet to be adequately studied in clinical trials. Hence, TXA use in this context is still an area of uncertainty, and its thrombogenic risks have yet to be studied as a primary outcome in any large prospective trial to date. Patients with any hypercoagulable risk factors, including HIV infection or any prior thrombotic history in which TXA use is being considered, should prompt a discussion among the perioperative physicians involved.